CN110545350B - Method for increasing audio playing volume in mobile phone hands-free state - Google Patents

Abstract

A method for increasing audio playing volume in a mobile phone hands-free state comprises the following steps: 1) adaptive gain, the process is as follows: assuming that the audio signal is digitally recordedB bit, then the dynamic range of the acoustic signal expressed by the specification is 6 x B decibels, i.e. the audio signal is [ -2^ (B-1),2^ (B-1) -1]Signed integer values in between; let the peak value of dynamic range B ^ 2^ (B-1) -1, and the original audio signal sequence is a₁、a₂、a₃,…,a_n…, multiplying the signal by an adaptive gain factor to become c₁、c₂、c₃,...,c_n,..,; 2) and (6) cutting off. The invention is beneficial to improving the audibility of mobile phone audio playing under acoustic noise environment; by implementing the scheme, the volume of the mobile phone can be increased to three modes from two modes, namely an earphone mode, a loudspeaker mode and the like, the third mode is a software power amplification mode, and the volume of mobile phone audio playing can be further increased when the mobile phone is opened in a hands-free mode.

Description

Method for increasing audio playing volume in mobile phone hands-free state

Technical Field

The invention relates to a method for controlling audio playing volume of a mobile phone.

Background

In sound cards of different specifications, the dynamic range of the sound card audio frequency can be calculated based on the number of sound card bits. The dynamic range of the traditional AC97 standard 16-bit sound card is 96 dB; the dynamic range of the HD Audio standard 32-bit sound card is 192 dB. The audio playing of the sound card can adjust the gain of the power amplifier or increase the playing volume by starting the hands-free power amplifier. For a mobile phone, audio playing is mainly in two modes except for power amplifier gain adjustment: a first, earphone mode, a second, speaker mode. The loudspeaker mode, namely the mode that the hands-free power amplifier is turned on, cannot ensure the maximum volume, so that a chance is provided for amplifying the volume to the maximum through the form of software power amplifier, and the method is particularly significant in noisy acoustic environment.

Disclosure of Invention

In order to overcome the defect that the playing volume can not be adjusted to the maximum even if the hands-free power amplifier is started by the conventional mobile phone audio playing setting mechanism, the invention provides a method for increasing the audio playing volume in a hands-free state of a mobile phone.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a method for increasing audio playing volume in a mobile phone hands-free state comprises the following steps:

1) adaptive gain, the process is as follows:

assuming that the audio signal bit number is denoted as B bit, the dynamic range of the acoustic signal expressed by the specification is 6 x B decibels, i.e. the audio signal is a signed integer value between [ -2^ (B-1),2^ (B-1) -1 ];

recording peak of dynamic rangeThe value B is 2^ (B-1) -1, the original audio signal sequence is a₁、a₂、a₃,…,a_n…, wherein a_iIs [ -2^ (B-1),2^ (B-1) -1]Signed integer between, multiplying the signal by an adaptive gain factor to become c₁、c₂、c₃,...,c_n,., wherein c_iIs [ -2^ (B-1),2^ (B-1) -1]Signed integer between, and the gain multiplication format is

c_i＝sgn(a_i)·[|a_i|·λ_i·υ_i+0.5]

2) The interception processing comprises the following steps:

wherein λ_iIs a gain coefficient, upsilon_iIs a damping coefficient, i.e. λ_i＞1,0＜υ_i< 1, but λ_iυ_i> 1 and the symbol [ 2 ]]For a gaussian rounding sign, sgn is the sign function: taking 1 for positive numbers and-1 for negative numbers;

gain factor

E_iThe filter is obtained through second-order IIR filtering,

E_i＝E_i-1·(1-α)+|a_i|·α

wherein alpha is more than 0 and less than 1;

υ_iobtained by second-order IIR filtering

N is the frame block length, 0 < beta < 1.

The technical conception of the invention is as follows: a volume self-adaptive adjusting method is designed, and the volume is adjusted to the maximum through a software power amplifier. The method has great benefits for improving the audibility of mobile phone audio playing in an acoustic noise environment; by implementing the scheme, the volume of the mobile phone can be increased to three modes from two modes, namely an earphone mode, a loudspeaker mode and the like, the third mode is a software power amplification mode, and the volume of mobile phone audio playing can be further increased when the mobile phone is opened in a hands-free mode.

The invention has the following beneficial effects: the audibility of the mobile phone audio playing can be improved.

Drawings

Fig. 1 is a flow chart of a method for increasing audio playback volume in a hands-free state of a mobile phone.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1, a method for increasing audio playing volume in a hands-free state of a mobile phone includes the following steps:

1) adaptive gain, the process is as follows:

assuming that the audio signal bit number is denoted as B bit, the dynamic range of the acoustic signal expressed by the specification is 6 x B decibels, i.e. the audio signal is a signed integer value between [ -2^ (B-1),2^ (B-1) -1 ];

let the peak value of dynamic range B ^ 2^ (B-1) -1, and the original audio signal sequence is a₁、a₂、a₃,…,a_n…, wherein a_iIs [ -2^ (B-1),2^ (B-1) -1]Signed integer between, multiplying the signal by an adaptive gain factor to become c₁、c₂、c₃,...,c_n,., wherein c_iIs [ -2^ (B-1),2^ (B-1) -1]Signed integer between, and the gain multiplication format is

c_i＝sgn(a_i)·[|a_i|·λ_i·υ_i+0.5]

2) The interception processing comprises the following steps:

wherein λ_iIs a gain coefficient, upsilon_iIs a damping coefficient, i.e. λ_i＞1,0＜υ_i< 1, but λ_iυ_i> 1 and the symbol [ 2 ]]For a gaussian rounding sign, sgn is the sign function: taking 1 for positive numbers and 1 for negative numbersTaking-1;

gain factor

E_iThe filter is obtained through second-order IIR filtering,

E_i＝E_i-1·(1-α)+|a_i|·α

where 0 < α < 1, typically much less than 1, e.g., α ═ 0.01 or α ═ 0.001;

υ_iobtained by second-order IIR filtering

N is the frame block length, 0 < β < 1, e.g., β ═ 0.3; upsilon is₀＝0.5。

The embodiment designs a volume self-adaptive adjusting method, and the volume is adjusted to the maximum in a software power amplifier mode. The method has great benefits for improving the audibility of mobile phone audio playing in an acoustic noise environment; by implementing the scheme, the volume of the mobile phone can be increased to three modes from two modes, namely an earphone mode, a loudspeaker mode and the like, the third mode is a software power amplification mode, and the volume of mobile phone audio playing can be further increased when the mobile phone is opened in a hands-free mode.

The scheme of the embodiment can prevent the audio signal value from overflowing the dynamic range.

Claims (1)

1. A method for increasing audio playing volume in a hand-free state of a mobile phone is characterized by comprising the following steps:

1) adaptive gain, the process is as follows:

assuming that the bit number of the audio signal is denoted as B bits, the dynamic range of the acoustic signal expressed by the audio signal with the bit number of B bits is 6dB, i.e. the audio signal is a signed integer value between [ -2^ (B-1),2^ (B-1) -1 ];

let the peak value of dynamic range B ^ 2^ (B-1) -1, and the original audio signal sequence is a₁、a₂、a₃,…,a_n…, wherein a_iIs [ 2 ]-2^(B-1),2^(B-1)-1]Signed integer between, multiplying the signal by an adaptive gain factor to become c₁、c₂、c₃,...,c_n,., wherein c_iIs [ -2^ (B-1),2^ (B-1) -1]Signed integer between, and the gain multiplication format is

c_i＝sgn(a_i)·[|a_i|·λ_i·υ_i+0.5]

2) The interception processing comprises the following steps:

wherein λ_iIs a gain coefficient, upsilon_iIs a damping coefficient, i.e. λ_i＞1,0＜υ_i< 1, but λ_iυ_i> 1 and the symbol [ 2 ]]For a gaussian rounding sign, sgn is the sign function: taking 1 for positive numbers and-1 for negative numbers;

gain factor

E_iThe filter is obtained through second-order IIR filtering,

E_i＝E_i-1·(1-α)+|a_i|·α

wherein alpha is more than 0 and less than 1;

υ_iobtained by second-order IIR filtering

N is the frame block length, 0 < beta < 1.

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